Acta neuropath. (Berl.) 33, 1--8 (1975) 9 by Springer-Verlag 1975
Originalarbeiten 9 Original Investigations
9 Travaux originaux
Symmetrical Infantile Thalamie Degeneration with Focal Cytoplasmic Calcification Mary A m b l e r a n d W i l l i a m O'Neff Department of Pathology (Neuropathology) and Pediatrics, Rhode Island Hospital Received May 26, 1975; Accepted July 10, 1975 Summary. Infantile thalamic degeneration is a rare clinico.pathological entity. Restricted location of the lesion and peculiar cytopathological changes serve to distinguish this disorder from. other common encephalopathies. Optical and ultrastructuraI studies demonstrate cytoplasmic caIeoph~rutes in previously viable eeils. According to current concepts of acute cellular reactions to injury and mechanism of intracellular calcification, the cytological changes cannot be attributed to either hypoxic ischemic cell change or dystrophic calcification. ]By analogy to other human and pathological material, the most likely basis for nondystrophic calcopherule formation is toxic or infectious injury with local synthesis, or autophagic or phagolysosomal degradation of cellular debris of specific chemical composition favoring calcium deposition.
Key words: Thalamus -- Cytoplasmic calcospherules -- Non-dystrophic -- Electron microscopy.
Introduction I n 1962 l%os~les a n d l%iggs described three cases of symznetrieal thalamic d e g e n e r a t i o n in i n f a n t s with p r o f o u n d neurological d i s a b i l i t y from birth, a n d early death. The p r i n c i p a l lesion consisted of ~halamic ce]l loss a n d astrogliosis. Residual s t r u c t u r e s r e s e m b l i n g fossilized neurons, b u t lacking histoehemie~lly d e m o n s t r a b l e iron or calcium, were noted. Interesr i n this e n t i t y focused on the restricted s y m m e t r i c a l site of the lesion a n d the patllogenesis of "pseudocaleified" cells (Richardson, 1962) This r e p o r t describes a f o u r t h case of i n f a n t i l e t h a l a m i c d e g e n e r a t i o n with both histoehemieal a n d u l t r a s t r u e t u r a l evidence of cytoplasmic calcification, a n d possible p a t h o g e n e t i c mechanisms.
Case Report A white male was born of a 42-week gestation and normal delivery. The pregaaancy was the t]rst for the 23-year-old mother. There was no family history of neurological illness. Birth weight was 7 lbs. 7 oz. Onset of spontaneous respirations was delayed 1 rain, Two hours after birth he was noted to have markedly increased muscle tone with opisthotonus. A neurological evaluation showed a jittery baby with diffusely increased muscle tone in all extremities, particularly in flexors of the upper extremities. Head circumference was 35.0 cm; transillumination was normal. Eontanelles were soft. Fundi were normal ; eye movements were full. Poor sucking reflex required garage feeding. ] ActaneuroDagh~(Berl.) Bd. 83
M. Ambler and W. O'Neil Table 1. Toxoplasma antibody titer Baby 2 weeks age
Mother Mother 3 months postpartum 4 months postpartum
Hemagglutination AB
1 : 128
1 : 256
1 : 32
Indirect fluorescence AB
--
1 : 128
1 : 64
During the nexts 2 weeks the baby continued to exhibit opisthotonic posturing, highpitched cry, and irregular, sometimes gasping, respiration with periods of apnea without cyanosis. Despite intensive supportive measures, apneie spells with bradycardia became more frequent and prolonged, refractory to therapy, and the child died at 3 weeks of age in cardiorespiratory arrest. Laboratory studies included normal hemogram and urineanalysis. Serum chemistries were: sodium 143, potassium 5.0, chloride 102, carbon dioxide 32, B U N 11, creatinine 0.9. Spinal fluid showed clear fluid with 1 red blood cell, protein 84 mg-~ glucose 76 mg-~ . CSF culture was negative. Urine amino acid screen showed normal pattern and output; urine mueopolysaccharide screen was normal. FTA-ABS test was non-reactive. Chromosomal analysis was normal male karyotype (46 xy). Cytomegalovirus antibody was negative. Toxoplasma antibody studies on child and mother are shown in Table 1.
Materials and Methods At necropsy brain and spinal cord were removed and fixed in 10% formalin. Following 20 days' fixation, samples were processed for light microscopy. Paraffin-embedded tissue was stained with H.-E., Von Kossa, PAS, and Prussian blue. For electron microscopical study samples from thalamus formalin fixed for I month were post-fixed in osmium-5 collidine buffer, dehydrated i:n alcohol propylene oxide, and embedded in epon. Toluidine blue stain was used for 1 ~ thick sections. Thin sections were stained with lead citrate and uranyl acetate and examined with a Siemens 1 A electron microscope.
Results Postmortem examination showed no anomalies of visceral organs. Brain weighed 390 g (ni-382 g). Coronal sections of brain and spinal cord showed no gross lesions. Microscopical study showed no meningeal or ependymal inflammation. Cortex was well formed with preserved cellular pattern. Lateral basal ganglia, hippoeampi, and brain stem nuclei were normal. In contrast, thalamic and hypothalamic nuclei showed severe cell loss and astrogliosis without necrosis or inflammation. Many residual cells were basophilic due to the presence of discrete or coalescent cytoplasmic globules, displacing nuclei and extending into proximal cell processes (Figs. 1 and 2). By optical criteria, these cells were judged to be neurons because of size, shape, and presence of satellite nuclei. The involved cells stained with Von Kossa and were negative with Prussian blue stains. The remaining cytoplasm, when visible, was faintly PAS-positive. Semithin sections emphasized the discrete nature of the globules and the nuclear preservation in involved ceils (Fig. 2).
Electron Microscopical Study G l o b u l a r d e n s e b o d i e s w e r e s e e n in l a r g e cells c o n t a i n i n g a b u n d a n t c y t o p l a s m , a n d e l o n g a t e d c e l l u l a r p r o j e c t i o n s (Fig. 3). T h e d e n s e b o d i e s v a r i e d in size a n d shape and were often partly segregated from remaining cytoplasm by smooth m e m b r a n e s (Fig. 4). T h e s e c y t o p l a s m i c i n c l u s i o n s w e r e p o l y m o r p h i c , c o m p o s e d of coarse a n d fine g r a n u l a r m a t e r i a l . L i n e a r d e n s i t i e s p r e s e n t e i t h e r as c o r e p a r t i c l e s
Symmetrical Infantile Thalamic Degeneration
3
Fig. 1. Two large "ferruginized" cells with densely stained cytoplasm. Note many round vesicular glial nuclei. (H.-E., original magnification • 166) Fig. 2. Inset--Semithin section. Large cell with discrete and coalescent cytoplasmic densities. (Toluidine blue, original magnification • 266)
or as marginal radiating spicules were observed both in stained and unstained sections (Figs.4 and 5). Despite extensive degenerative changes in cytoplasm, attributed in part to postmortem and formalin fixation artifact, the nuclei, granular endoplasmic reticulum, and mitochondria were relatively well preserved (Fig.4). Floccular matrical densities lacking spicules or annular configuration were seen within mitochondrial cristae and adjacent to inner membranes. Synaptic contacts, cytoplasmic microfilaments, and microtubules were not identified. Satellite nuclei were either large and vacuolated or small and condensed. Similar cells with organelle-poor cytoplasm in surrounding neuropil were considered glial cells (Fig. 3). Astroglial fibrils were infrequent and most cells judged to be glia! contained no cytoplasmic densities. Discussion The case described in this report shows remarkable similarities of clinical presentation, site of lesion, and histological change to those described by Rosales and Riggs (1962). Neuropathological interest relates to two unusual findings: the restricted thalamic distribution, and the peculiar eytopathological change (Richardson, 1962). 1"
4
M. Ambler and W. O'Neil
Fig. 3. Electron photomicrograph of large cell with preserved marginal nucleus (bottom). Globular amorphous inclusions of varied size fill cytoplasm and proximal cell process. Two satellite cells with ratified cytoplasm are seen. (Original magnification • 1333)
Restricted Thalamic Distribution Regional vulnerability seen in a variety of neuropathologieal disorders is generally attributed to peculiarities in local vascular architecture or specific metabolic requirements of certain cellular masses. However, because thalamic nuclei receive blood supply from multiple sources, they are rarely totally or exclusively damaged by ischemic or hypoxic insults. Restricted symmetrical thalamic degeneration is an unusual pathological observation of unknown etiology (Schu]man, 1957 ; Stern, 1939). In a recent case report local vascular changes are assumed to be of etiologic importance (De-Girolami et al., 1974). Preponderant thalamic cell degeneration has been emphasized in storage diseases (Lemieux, 1954; Gilles and Deuel, 1971), and in experimental rat scrapie infection (Field et al., 1967). Protbund neurological disability associated with bilateral thalamic cell loss is well recognized.
Fig. 4. Portion of cytoplasmic inclusion showing granular matrix and linear spicules as core densities or marginal rays. Inclusions are partly surrounded by single membrane. Note edge of nucleus, RER, and mitochondria with floccular densities and preserved eristae left lower margin. (Original magnification • 12000) Fig.5. Electron photomicrograph of unstained section. Cytoplasmic inclusion with linear spicules typical of calcium crystals. (Original magnification • 16000)
Symmegrica] Infantile Thalamic Degeneration
Fig. r
Fig, 5
5
6
M. Amblerand W. O'Neil
Cytopathology Involved cells appear to be relatively preserved and previously viable cells. Ultrastructural changes in nuclei and mitoehondria are considered compatible with those observed in acute (Stage 5) cellular necrosis (Trump et al., 1973) consistent with terminal shock. In contrast, the cytoplasmic alterations, probably of more chronic age, consist of discrete polymorphous spherular bodies with spicular densities typical of calcium apatite crystals. Investigation of experimental cellular calcification indicates that dystrophic mineral deposition may occur prior to severe ultrastrnctural cytological disorganization. Initiai calcium deposition is seen in mitochondria (Gritzka and Trump, 1968) or sarcoplasmic reticulum of skeletal muscle (Bonucci and Sadun, 1972) presumably related to the role of these organelles in intracellular movement or storage of calcium. Diffuse cytoplasmic calcification is accompanied by biochemical degradation of cell sap perhaps favoring mineral deposition (Bonucci and Sadun, 1972, 1973). Experimental ischemic cell damage is not accompanied by either mitochondrial or cytoplasmic ca]cification (Mergner et al., 1972). Dystrophic parenchymal cellular mineralization, therefore, follows certain ~ypes of progTessive cell injury, occurs only in conjunction with mitochondrial mineral deposition, and is evidence of lethal or irreversible change. Focal cytoplasmic calcospherule formation in presumably viable cells judged by ultrastructural preservation of nuclei and cellular organelles is a rare pathological observation. Pathognomonic cytoplasmic inclusions in malakoplakia have recently been identified: as calcified bacterial debris in phagolysosomes of histiocytes (Lou and Teplitz, 1974). Chou and Fukuhara (1973) report membrane-bound cytoplasmic caleospherite production in glial cells of cerebellum and dorsal root ganglia following chronic methyl mercury poisoning. Focal cellular calcifie deposits are noted in macrophage phagosomes in encephalomalacia (Iizuka and Spalhe, 1973). Nondystrophic cytoplasmic calcospherule formation appears to be a focal cellular reaction following accumulation of locally formed, pinocytized or phagoeytized intracellular debris of appropriate biochemical composition of pH to favor calcium deposition.
Etiology o/In/antile Thalamic Degeneration Although involved cells optically resemble neurons rather than glial or microglial cells, distinguishing fine structural features were not identified; and etiologic considerations must include disorders affecting parenchymal or supportive elements. Ferruginized cells found in cerebral gray matter (without other visible evidence of parenchymal necrosis) are most frequently attributed to hypoxic-ischemie neuronal injury with dystrophic mineralization. They have not been subjected to ul~ras~ruc~ural study. The sequential ultrastructural alterations of neurons in hypoxic-isehemie insult (Brown and Brierley, 1972) include mitochondrial swelling, cytoplasmic condensation, and encrustation, but neither mitoehondrial nor cytoplasmic calcification is described. Therefore, ultrastructural preservation of mitochondria and lack of cristal calcification argues against either hypoxic-ischemic injury or dystrophic mineralization as the basis for the cytopathological change.
Symmetrical Infantile Thalamic Degeneration Calcospherite production noted following chronic m e r c u r y poisoning is of particular interest as it describes both focal cytoplasmic injury and preferential susceptibility of glial cells in selected regions of nervous system (Chou and ]?ukuhara, 1973). Sublethal cellular necrosis and mineralization subsequent to chronic toxic insult is an attractive hypothetical basis for infantile thalamie degeneration. Microorganisms m a y penetrate and replicate in a n y neurogliM cells. I n our ease, a diagnosis of congenital toxoplasmosis was considered. Toxoplasmosis organisms have been visualized within cytoplasmic vacuoles of neurons and glia prior to cell lysis (Ghatak and Zimmerman, 1973). No mineral deposition is described. Failure to identify intraecllular microorganisms does not, however, dismiss the possibility of cellular parasitism particularly in healed or chronic stage. The cause of thalamic cell loss and calcification cannot be definitely established in this study. Our findings, however, support the concept t h a t cytoplasmic ealcospherule formation, previously described only in cells with scavenger potential, is a form of nondystrophic cellular calcification distinguished by its rare occurrence. Limited data suggests the pathogcnetie stimulus is toxic or infectious in origin producing chronic evidence of focal non-lethal cytoplasmic injury.
References Bonucci, E., Sadun, 1%.: An electron microscope study on experimental calcification of skeletal muscle. Clin. 0rthop. 88, 197--217 (1972) Bonucci, E., Sadun, R. : Experimental calcification of the myocardium. Amer. J. Path. 71, 167--192 (1973) Brown, A. W., Brierley, J. B. : Anoxic~ischemic cell change in rat brain: Light microscopic and fine structural observations. J. neurol. Sci. 23, 9 - 2 2 (1972) Chou, S. M., Fukuhara, N. : EM studies on calcospherites induced in cerebellar granular layers of rats by chronic methyl mercury poisoning. J. Neuropath. exp. Neurol. 32, 175--176 (1973) DeGirolami, U., Hass, M. L., Richardson, E. P. : Subacute diencephalic angioencephalopathy. J. neurol. Sci. 22, ][97--210 (1974) Field, E. J., Raine, C. S., Joyce, G. : Scrapie in the rat: An electron microscope study. Acta neuropath. (Berl.) S, 47--56 (1967) Ghatak, N. R., Zimmerman, H. R. : Fine structure of toxoplasma in the human brain. Arch. Path. 95, 276--283 (][973) Gilles, F. H., Denel, R. K. : Neuronal cytoplasmic globules in the brain in Morquio's syndrome. Arch. Neurol. (Chic.) 25, 393--403 (][971) Gritzka, T. L., Trump, B. F. : Renal tubular lesions caused by mercuric chloride. Amer. J. Path. 52, ][225--1277 (][968) Iizuka, R., Spalhe, G. : Giant cell pseudocMcium necrosis in the early stages of cortical necrosis due to arteriosclerotic inclusion. Acta neuropath. (Berl.) 28, 313--319 (1973) Lemieux, L. H.: The thalamic pathology of amaurotic family idiocy. J. Neuropath. exp. Neurol. 18, 343--352 (1954) Lou, T.Y., Teplitz, C.: Malakoplakia: Pathogenesis and ultrastructural morphogenesis. Human Path. 5, 191--207 (1974) Mergner, W.J., Garbus, J., Dees, J. :H., Valigorsky, J.M., Trump, B. F. : Structural and functional changes in human kidney and liver mitochondria in acute cell injury after shock and trauma. Amcr. J. Path. 66, 363 (1972) Richardson, E. P. : In discussion of symmetrical thamalic degeneration in infants. J. Neuropath. exp. Neurol. 21,300--301 (1962)
8
M. Ambler and W. 0'Neil
Rosales, R. K., Riggs, H. A. : Symmetrical thalamic degeneration in infants. J. Heuropath. exp. Neurol. 21, 372--376 (1962) Schulman, S. : Bilateral symmetrical degeneration of the thalamus. J. Neuropath. exp. Neurol. 16, 446 (1957) Stern, K. : Severe dementia associated with bilateral symmetrical degeneration of the thalamus. Brain 6~, 157--171 (1939) Trump, B.F., Valigorsky, J. 1K., Dees, J . H . , Mergner, W . J . , Kim, K.M., Jones, R. T.: Pendergrass, R. E., Garbus, J., Cowley, R. A. : Cellular changes in human disease. Human Path. 4, 89--109 (1973) Dr. Mary Ambler Department of Pathology (Neuropathology) Rhode Island Hospital Providence, R. I. 02902 U.S.A.
Originalarbeiten 9 Original Investigations
9 Travaux originaux
Symmetrical Infantile Thalamie Degeneration with Focal Cytoplasmic Calcification Mary A m b l e r a n d W i l l i a m O'Neff Department of Pathology (Neuropathology) and Pediatrics, Rhode Island Hospital Received May 26, 1975; Accepted July 10, 1975 Summary. Infantile thalamic degeneration is a rare clinico.pathological entity. Restricted location of the lesion and peculiar cytopathological changes serve to distinguish this disorder from. other common encephalopathies. Optical and ultrastructuraI studies demonstrate cytoplasmic caIeoph~rutes in previously viable eeils. According to current concepts of acute cellular reactions to injury and mechanism of intracellular calcification, the cytological changes cannot be attributed to either hypoxic ischemic cell change or dystrophic calcification. ]By analogy to other human and pathological material, the most likely basis for nondystrophic calcopherule formation is toxic or infectious injury with local synthesis, or autophagic or phagolysosomal degradation of cellular debris of specific chemical composition favoring calcium deposition.
Key words: Thalamus -- Cytoplasmic calcospherules -- Non-dystrophic -- Electron microscopy.
Introduction I n 1962 l%os~les a n d l%iggs described three cases of symznetrieal thalamic d e g e n e r a t i o n in i n f a n t s with p r o f o u n d neurological d i s a b i l i t y from birth, a n d early death. The p r i n c i p a l lesion consisted of ~halamic ce]l loss a n d astrogliosis. Residual s t r u c t u r e s r e s e m b l i n g fossilized neurons, b u t lacking histoehemie~lly d e m o n s t r a b l e iron or calcium, were noted. Interesr i n this e n t i t y focused on the restricted s y m m e t r i c a l site of the lesion a n d the patllogenesis of "pseudocaleified" cells (Richardson, 1962) This r e p o r t describes a f o u r t h case of i n f a n t i l e t h a l a m i c d e g e n e r a t i o n with both histoehemieal a n d u l t r a s t r u e t u r a l evidence of cytoplasmic calcification, a n d possible p a t h o g e n e t i c mechanisms.
Case Report A white male was born of a 42-week gestation and normal delivery. The pregaaancy was the t]rst for the 23-year-old mother. There was no family history of neurological illness. Birth weight was 7 lbs. 7 oz. Onset of spontaneous respirations was delayed 1 rain, Two hours after birth he was noted to have markedly increased muscle tone with opisthotonus. A neurological evaluation showed a jittery baby with diffusely increased muscle tone in all extremities, particularly in flexors of the upper extremities. Head circumference was 35.0 cm; transillumination was normal. Eontanelles were soft. Fundi were normal ; eye movements were full. Poor sucking reflex required garage feeding. ] ActaneuroDagh~(Berl.) Bd. 83
M. Ambler and W. O'Neil Table 1. Toxoplasma antibody titer Baby 2 weeks age
Mother Mother 3 months postpartum 4 months postpartum
Hemagglutination AB
1 : 128
1 : 256
1 : 32
Indirect fluorescence AB
--
1 : 128
1 : 64
During the nexts 2 weeks the baby continued to exhibit opisthotonic posturing, highpitched cry, and irregular, sometimes gasping, respiration with periods of apnea without cyanosis. Despite intensive supportive measures, apneie spells with bradycardia became more frequent and prolonged, refractory to therapy, and the child died at 3 weeks of age in cardiorespiratory arrest. Laboratory studies included normal hemogram and urineanalysis. Serum chemistries were: sodium 143, potassium 5.0, chloride 102, carbon dioxide 32, B U N 11, creatinine 0.9. Spinal fluid showed clear fluid with 1 red blood cell, protein 84 mg-~ glucose 76 mg-~ . CSF culture was negative. Urine amino acid screen showed normal pattern and output; urine mueopolysaccharide screen was normal. FTA-ABS test was non-reactive. Chromosomal analysis was normal male karyotype (46 xy). Cytomegalovirus antibody was negative. Toxoplasma antibody studies on child and mother are shown in Table 1.
Materials and Methods At necropsy brain and spinal cord were removed and fixed in 10% formalin. Following 20 days' fixation, samples were processed for light microscopy. Paraffin-embedded tissue was stained with H.-E., Von Kossa, PAS, and Prussian blue. For electron microscopical study samples from thalamus formalin fixed for I month were post-fixed in osmium-5 collidine buffer, dehydrated i:n alcohol propylene oxide, and embedded in epon. Toluidine blue stain was used for 1 ~ thick sections. Thin sections were stained with lead citrate and uranyl acetate and examined with a Siemens 1 A electron microscope.
Results Postmortem examination showed no anomalies of visceral organs. Brain weighed 390 g (ni-382 g). Coronal sections of brain and spinal cord showed no gross lesions. Microscopical study showed no meningeal or ependymal inflammation. Cortex was well formed with preserved cellular pattern. Lateral basal ganglia, hippoeampi, and brain stem nuclei were normal. In contrast, thalamic and hypothalamic nuclei showed severe cell loss and astrogliosis without necrosis or inflammation. Many residual cells were basophilic due to the presence of discrete or coalescent cytoplasmic globules, displacing nuclei and extending into proximal cell processes (Figs. 1 and 2). By optical criteria, these cells were judged to be neurons because of size, shape, and presence of satellite nuclei. The involved cells stained with Von Kossa and were negative with Prussian blue stains. The remaining cytoplasm, when visible, was faintly PAS-positive. Semithin sections emphasized the discrete nature of the globules and the nuclear preservation in involved ceils (Fig. 2).
Electron Microscopical Study G l o b u l a r d e n s e b o d i e s w e r e s e e n in l a r g e cells c o n t a i n i n g a b u n d a n t c y t o p l a s m , a n d e l o n g a t e d c e l l u l a r p r o j e c t i o n s (Fig. 3). T h e d e n s e b o d i e s v a r i e d in size a n d shape and were often partly segregated from remaining cytoplasm by smooth m e m b r a n e s (Fig. 4). T h e s e c y t o p l a s m i c i n c l u s i o n s w e r e p o l y m o r p h i c , c o m p o s e d of coarse a n d fine g r a n u l a r m a t e r i a l . L i n e a r d e n s i t i e s p r e s e n t e i t h e r as c o r e p a r t i c l e s
Symmetrical Infantile Thalamic Degeneration
3
Fig. 1. Two large "ferruginized" cells with densely stained cytoplasm. Note many round vesicular glial nuclei. (H.-E., original magnification • 166) Fig. 2. Inset--Semithin section. Large cell with discrete and coalescent cytoplasmic densities. (Toluidine blue, original magnification • 266)
or as marginal radiating spicules were observed both in stained and unstained sections (Figs.4 and 5). Despite extensive degenerative changes in cytoplasm, attributed in part to postmortem and formalin fixation artifact, the nuclei, granular endoplasmic reticulum, and mitochondria were relatively well preserved (Fig.4). Floccular matrical densities lacking spicules or annular configuration were seen within mitochondrial cristae and adjacent to inner membranes. Synaptic contacts, cytoplasmic microfilaments, and microtubules were not identified. Satellite nuclei were either large and vacuolated or small and condensed. Similar cells with organelle-poor cytoplasm in surrounding neuropil were considered glial cells (Fig. 3). Astroglial fibrils were infrequent and most cells judged to be glia! contained no cytoplasmic densities. Discussion The case described in this report shows remarkable similarities of clinical presentation, site of lesion, and histological change to those described by Rosales and Riggs (1962). Neuropathological interest relates to two unusual findings: the restricted thalamic distribution, and the peculiar eytopathological change (Richardson, 1962). 1"
4
M. Ambler and W. O'Neil
Fig. 3. Electron photomicrograph of large cell with preserved marginal nucleus (bottom). Globular amorphous inclusions of varied size fill cytoplasm and proximal cell process. Two satellite cells with ratified cytoplasm are seen. (Original magnification • 1333)
Restricted Thalamic Distribution Regional vulnerability seen in a variety of neuropathologieal disorders is generally attributed to peculiarities in local vascular architecture or specific metabolic requirements of certain cellular masses. However, because thalamic nuclei receive blood supply from multiple sources, they are rarely totally or exclusively damaged by ischemic or hypoxic insults. Restricted symmetrical thalamic degeneration is an unusual pathological observation of unknown etiology (Schu]man, 1957 ; Stern, 1939). In a recent case report local vascular changes are assumed to be of etiologic importance (De-Girolami et al., 1974). Preponderant thalamic cell degeneration has been emphasized in storage diseases (Lemieux, 1954; Gilles and Deuel, 1971), and in experimental rat scrapie infection (Field et al., 1967). Protbund neurological disability associated with bilateral thalamic cell loss is well recognized.
Fig. 4. Portion of cytoplasmic inclusion showing granular matrix and linear spicules as core densities or marginal rays. Inclusions are partly surrounded by single membrane. Note edge of nucleus, RER, and mitochondria with floccular densities and preserved eristae left lower margin. (Original magnification • 12000) Fig.5. Electron photomicrograph of unstained section. Cytoplasmic inclusion with linear spicules typical of calcium crystals. (Original magnification • 16000)
Symmegrica] Infantile Thalamic Degeneration
Fig. r
Fig, 5
5
6
M. Amblerand W. O'Neil
Cytopathology Involved cells appear to be relatively preserved and previously viable cells. Ultrastructural changes in nuclei and mitoehondria are considered compatible with those observed in acute (Stage 5) cellular necrosis (Trump et al., 1973) consistent with terminal shock. In contrast, the cytoplasmic alterations, probably of more chronic age, consist of discrete polymorphous spherular bodies with spicular densities typical of calcium apatite crystals. Investigation of experimental cellular calcification indicates that dystrophic mineral deposition may occur prior to severe ultrastrnctural cytological disorganization. Initiai calcium deposition is seen in mitochondria (Gritzka and Trump, 1968) or sarcoplasmic reticulum of skeletal muscle (Bonucci and Sadun, 1972) presumably related to the role of these organelles in intracellular movement or storage of calcium. Diffuse cytoplasmic calcification is accompanied by biochemical degradation of cell sap perhaps favoring mineral deposition (Bonucci and Sadun, 1972, 1973). Experimental ischemic cell damage is not accompanied by either mitochondrial or cytoplasmic ca]cification (Mergner et al., 1972). Dystrophic parenchymal cellular mineralization, therefore, follows certain ~ypes of progTessive cell injury, occurs only in conjunction with mitochondrial mineral deposition, and is evidence of lethal or irreversible change. Focal cytoplasmic calcospherule formation in presumably viable cells judged by ultrastructural preservation of nuclei and cellular organelles is a rare pathological observation. Pathognomonic cytoplasmic inclusions in malakoplakia have recently been identified: as calcified bacterial debris in phagolysosomes of histiocytes (Lou and Teplitz, 1974). Chou and Fukuhara (1973) report membrane-bound cytoplasmic caleospherite production in glial cells of cerebellum and dorsal root ganglia following chronic methyl mercury poisoning. Focal cellular calcifie deposits are noted in macrophage phagosomes in encephalomalacia (Iizuka and Spalhe, 1973). Nondystrophic cytoplasmic calcospherule formation appears to be a focal cellular reaction following accumulation of locally formed, pinocytized or phagoeytized intracellular debris of appropriate biochemical composition of pH to favor calcium deposition.
Etiology o/In/antile Thalamic Degeneration Although involved cells optically resemble neurons rather than glial or microglial cells, distinguishing fine structural features were not identified; and etiologic considerations must include disorders affecting parenchymal or supportive elements. Ferruginized cells found in cerebral gray matter (without other visible evidence of parenchymal necrosis) are most frequently attributed to hypoxic-ischemie neuronal injury with dystrophic mineralization. They have not been subjected to ul~ras~ruc~ural study. The sequential ultrastructural alterations of neurons in hypoxic-isehemie insult (Brown and Brierley, 1972) include mitochondrial swelling, cytoplasmic condensation, and encrustation, but neither mitoehondrial nor cytoplasmic calcification is described. Therefore, ultrastructural preservation of mitochondria and lack of cristal calcification argues against either hypoxic-ischemic injury or dystrophic mineralization as the basis for the cytopathological change.
Symmetrical Infantile Thalamic Degeneration Calcospherite production noted following chronic m e r c u r y poisoning is of particular interest as it describes both focal cytoplasmic injury and preferential susceptibility of glial cells in selected regions of nervous system (Chou and ]?ukuhara, 1973). Sublethal cellular necrosis and mineralization subsequent to chronic toxic insult is an attractive hypothetical basis for infantile thalamie degeneration. Microorganisms m a y penetrate and replicate in a n y neurogliM cells. I n our ease, a diagnosis of congenital toxoplasmosis was considered. Toxoplasmosis organisms have been visualized within cytoplasmic vacuoles of neurons and glia prior to cell lysis (Ghatak and Zimmerman, 1973). No mineral deposition is described. Failure to identify intraecllular microorganisms does not, however, dismiss the possibility of cellular parasitism particularly in healed or chronic stage. The cause of thalamic cell loss and calcification cannot be definitely established in this study. Our findings, however, support the concept t h a t cytoplasmic ealcospherule formation, previously described only in cells with scavenger potential, is a form of nondystrophic cellular calcification distinguished by its rare occurrence. Limited data suggests the pathogcnetie stimulus is toxic or infectious in origin producing chronic evidence of focal non-lethal cytoplasmic injury.
References Bonucci, E., Sadun, 1%.: An electron microscope study on experimental calcification of skeletal muscle. Clin. 0rthop. 88, 197--217 (1972) Bonucci, E., Sadun, R. : Experimental calcification of the myocardium. Amer. J. Path. 71, 167--192 (1973) Brown, A. W., Brierley, J. B. : Anoxic~ischemic cell change in rat brain: Light microscopic and fine structural observations. J. neurol. Sci. 23, 9 - 2 2 (1972) Chou, S. M., Fukuhara, N. : EM studies on calcospherites induced in cerebellar granular layers of rats by chronic methyl mercury poisoning. J. Neuropath. exp. Neurol. 32, 175--176 (1973) DeGirolami, U., Hass, M. L., Richardson, E. P. : Subacute diencephalic angioencephalopathy. J. neurol. Sci. 22, ][97--210 (1974) Field, E. J., Raine, C. S., Joyce, G. : Scrapie in the rat: An electron microscope study. Acta neuropath. (Berl.) S, 47--56 (1967) Ghatak, N. R., Zimmerman, H. R. : Fine structure of toxoplasma in the human brain. Arch. Path. 95, 276--283 (][973) Gilles, F. H., Denel, R. K. : Neuronal cytoplasmic globules in the brain in Morquio's syndrome. Arch. Neurol. (Chic.) 25, 393--403 (][971) Gritzka, T. L., Trump, B. F. : Renal tubular lesions caused by mercuric chloride. Amer. J. Path. 52, ][225--1277 (][968) Iizuka, R., Spalhe, G. : Giant cell pseudocMcium necrosis in the early stages of cortical necrosis due to arteriosclerotic inclusion. Acta neuropath. (Berl.) 28, 313--319 (1973) Lemieux, L. H.: The thalamic pathology of amaurotic family idiocy. J. Neuropath. exp. Neurol. 18, 343--352 (1954) Lou, T.Y., Teplitz, C.: Malakoplakia: Pathogenesis and ultrastructural morphogenesis. Human Path. 5, 191--207 (1974) Mergner, W.J., Garbus, J., Dees, J. :H., Valigorsky, J.M., Trump, B. F. : Structural and functional changes in human kidney and liver mitochondria in acute cell injury after shock and trauma. Amcr. J. Path. 66, 363 (1972) Richardson, E. P. : In discussion of symmetrical thamalic degeneration in infants. J. Neuropath. exp. Neurol. 21,300--301 (1962)
8
M. Ambler and W. 0'Neil
Rosales, R. K., Riggs, H. A. : Symmetrical thalamic degeneration in infants. J. Heuropath. exp. Neurol. 21, 372--376 (1962) Schulman, S. : Bilateral symmetrical degeneration of the thalamus. J. Neuropath. exp. Neurol. 16, 446 (1957) Stern, K. : Severe dementia associated with bilateral symmetrical degeneration of the thalamus. Brain 6~, 157--171 (1939) Trump, B.F., Valigorsky, J. 1K., Dees, J . H . , Mergner, W . J . , Kim, K.M., Jones, R. T.: Pendergrass, R. E., Garbus, J., Cowley, R. A. : Cellular changes in human disease. Human Path. 4, 89--109 (1973) Dr. Mary Ambler Department of Pathology (Neuropathology) Rhode Island Hospital Providence, R. I. 02902 U.S.A.
